I had shingles years ago when I was 26. It certainly does happen in younger people, more often than would be expected or really known. Even people with normal immune systems can get shingles if they're under a big amount of stress or something, or if their immune system is struggling due to an illness or something. Not all shingles cases in even younger people can be linked to the vaccine, and even in older people where it's always been more common for them to get shingles long before covid ever was introduced. I really don't think one can tell anything from someone getting shingles.